Fix is_method_of (cf #310), add regression test case

i3pystatus/core/modules.py

@@ -10,8 +10,12 @@ from i3pystatus.core.command import run_through_shell
 
 def is_method_of(method, object):
     """Decide whether ``method`` is contained within the MRO of ``object``."""
+    if not callable(method) or not hasattr(method, "__name__"):
+        return False
+    if inspect.ismethod(method):
+        return method.__self__ is object
     for cls in inspect.getmro(object.__class__):
-        if method in cls.__dict__.values():
+        if cls.__dict__.get(method.__name__, None) is method:
             return True
     return False
 

tests/test_core_modules.py

@@ -4,6 +4,7 @@ from unittest.mock import MagicMock
 import pytest
 
 from i3pystatus import IntervalModule
+from i3pystatus.core.modules import is_method_of
 
 left_click = 1
 right_click = 3
@@ -120,3 +121,27 @@ def test_callback_handler_function():
     dut = TestClicks()
     dut.on_click(scroll_up)
     callback_mock.callback.assert_called_once_with("upscroll")
+
+
+def test_is_method_of():
+    class TestClass:
+        def method(self):
+            pass
+
+        # member assigned functions cannot be distinguished in unbound state
+        # by principle from methods, since both are functions. However, in
+        # most cases it can still be shown correctly that a member assigned
+        # function is not a method, since the member name and function name
+        # are different (in this example the assigned member is 'assigned_function',
+        # while the name of the function is 'len', hence is_method_of can say for
+        # sure that assigned_function isn't a method
+        assigned_function = len
+        member = 1234
+        string_member = "abcd"
+
+    object = TestClass()
+    for source_object in [object, TestClass]:
+        assert is_method_of(source_object.method, object)
+        assert not is_method_of(source_object.assigned_function, object)
+        assert not is_method_of(source_object.member, object)
+        assert not is_method_of(source_object.string_member, object)